GenerateSuperInterfaceProcessor.java

/*
 * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import com.sun.tools.javac.util.Assert;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Set;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.RoundEnvironment;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;

@SupportedAnnotationTypes("*")
public class GenerateSuperInterfaceProcessor extends AbstractProcessor {

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        for (Element el : roundEnv.getElementsAnnotatedWith(Generate.class)) {
            Generate g = el.getAnnotation(Generate.class);

            Assert.checkNonNull(g);

            try (OutputStream out =
                    processingEnv.getFiler().createSourceFile(g.fileName()).openOutputStream()) {
                out.write(g.content().getBytes());
            } catch (IOException ex) {
                throw new IllegalStateException(ex);
            }
        }

        return false;
    }

}

@interface Generate {
    String fileName();
    String content();
}